Evaluate the L2C guinea pig leukemia in a series of experiments designed to test various agents for their capacity to act as immunotherapy in the treatment of the leukemia. Such agents may include thymosin, levamisole, BCG, Corynebacterium parvum, immune RNA, leukemia cells, and cell fractions. The parameters of dose, route, and schedule of administration will be important aspects of this program. Successful single agent therapeutic attempts will be considered in the subsequent evaluation of combinations of agents, both simultaneously and in sequence. The Principal Investigator is to select one immunotherapy agent and show unequivocally that an immunotherapeutic effect can be demonstrated in this tumor model before additional studies are undertaken.